The Study And Development Of Electronic Beam Control System In Warp Knitting

Warp letting-off rule and the domination principle of electronic beam controlsystem in warp knitting are studied, based on which electronic beam control systemis developed in this paper.First the development of the beam control system in warp knitting machine isintroduced, and the application of beam control system in home and abroad are analyzed,the gap between which can be seen obviously. Electronic beam control system developedby ourselves is eagerly in demand, to replace the wearing out FAG mechanical beamcontrol system. Then, the relation diagrams between beam parameter and time, beamrotation speed and time, beam rotation speed and beam parameter are described throughMatlab program. In order to study the dynamic yarn tension variation rule and therelationship between yarn tension and run-in value, a digital method testing dynamicyarn tension based on computer is designed in this paper. Yarn tensions in differentrun-in value are tested using existing facility. The test result indicates three wavecrests occur during one loop forming period that is over-lapping limiting position,under-lapping limiting position and knock-over position, and two troughs duringknock-over period. The maximum and minimum value decrease when run-in value rises,and the fluctuation, described with mean square root, decreases too. The electronicbeam control systems are divided into three types concerned with run-in value, linear,two-step, and sequential, and the control principle of each type is analyzed separatelyin detail. Velocity closed loop is used in linear and two-step letting-off system,while position and Velocity double closed loop is used in sequential system. Bothcontrol algorithm of the two closed loop are deduced. The emphasis of this paper isput forward in the end, which describes the design and practice of electronic beamcontrol system in warp knitting. The system uses FCS (field control system) technologybased on single chip;each beam is droved separately by servo-motor;each servo-motoris controlled separately by each beam control unit, while each control unit is managedcentrally by the super controller. The processing parameters are input and outputthrough human-computer interface, while the field data acquisition and real-timecomputation are managed by the controller based on single chip. The application testingresult indicates that the electronic beam control system developed has excellentperformance and can replace FAG mechanical beam control system.